CODED SIGNAL SEPARATING/MERGING DEVICE, GENERATOR AND EXTRACTING DEVICE FOR DIFFERENCE CODED SIGNAL, AND METHOD AND PROGRAM FOR SEPARATING/MERGING CODED SIGNAL

摘要

PROBLEM TO BE SOLVED: To improve quality without receiving an original bit stream before reducing a code quantity from a bit stream after reducing the code quantity.

SOLUTION: A stream separating device 1000 inputs a first coded signal before reducing the code quantity, applies code quantity conversion processing to the first coded signal, converts the signal into a second coded signal having a reduced code quantity and outputs the converted signal, and generates an expanded difference coded signal having information about a change in coefficient value and outputs the generated signal from one part of the difference signal between the first coded signal and the second coded signal. A stream merging device 2000 inputs the second coded signal, inputs the expanded difference coded signal, and synthesizes the second coded signal with the expanded difference coded signal to generate a synthesized coded signal. Devices 1000 and 2000 can approximate the second coded signal after reducing the code quantity to the first coded signal before reducing the code quantity without receiving the original signal, and can improve the quality.

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